Hopping master in wireless conference

ABSTRACT

A first radio has duplex communication with a second radio and a third radio, without using a base station by using a multiple-access protocol system. The first radio is configured to perform as a master radio and then switch to be a slave radio. A master radio provides timing synchronization and/or assigns transmission slots for radios in the multiple-access protocol system.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/833,911, filed on Aug. 24, 2015, entitled “Hopping Master In WirelessConference,” which application is a continuation of U.S. patentapplication Ser. No. 14/225,183, filed on Mar. 25, 2014, now U.S. Pat.No. 9,143,309, issued Sep. 22, 2015, entitled “Hopping Master InWireless Conference,” which application claims the benefit of and is acontinuation-in-part of U.S. patent application Ser. No. 13/863,282,filed on Apr. 15, 2013, which claims priority to U.S. Patent ApplicationNo. 61/751,727, filed on Jan. 11, 2013, U.S. Patent Application No.61/681,399, filed on Aug. 9, 2012, and U.S. Patent Application No.61/623,662, filed on Apr. 13, 2012; each of which is expresslyincorporated by reference in its entirety for all purposes.

BACKGROUND

This disclosure relates in general to radio communication, and morespecifically, without limitation, to time-division multiplexedcommunication. Two-way radios enable wireless communication between twoor more people. To operate, many radios require either a push-to-talk(PTT) button or a voice operated switch (VOX). For example,walkie-talkies today require either a PTT button or VOX. Onedisadvantage of both PTT and VOX is that both PTT and VOX communicationsare half-duplex. In half-duplex communication, a radio can eithertransmit or receive at a given time, not both. In this application, theterm PTT radio generally refers to radios using half-duplexcommunication where a user can either speak or listen at a given time,not both.

Full-duplex communication, commonly referred to as duplex communication,permits a radio to simultaneously transmit and receive at the same time,enabling a user of a duplex radio to both speak and listen at the sametime. One way a radio can operate in a duplex mode, without needing aPTT button or VOX, is by using a base station. An example of wirelessradios connected by a base station, and thus enabling full-duplexcommunication, is two users talking to each other using cell phones.Another example of wireless radios connected by a base station is a hometelephone system with wireless telephones that can be placed in aconferencing mode.

SUMMARY

Radios can operate in duplex communication without a base station usinga multiple access protocol. For example, by using time-divisionmultiplexing such as a time-division multiple access (TDMA) protocolradios can communicate with each other without using a base station. Anexample of radios communicating using a TDMA protocol system to create awireless-conferencing system that does not use a base station isdisclosed in U.S. patent application Ser. No. 10/194,115, filed on Jul.11, 2002. A wireless-conferencing system that does not use a basestation (e.g., using a multiple access protocol), and in someembodiments is similar to that disclosed in the '115 application, isreferred to in this application as a multivoice system. A radio that isconfigured to operate in a wireless-conferencing system is referred to,in this application, as a multivoice radio or an MVR, or both. In someembodiments, a multivoice radio is simply referred to, in thisapplication, as a radio because it is understood from the context thatthe radio is a multivoice radio part of a multivoice system. Amultivoice system allows users to speak and listen, at the same time, toothers using multivoice radios. In some embodiments, a multivoice systemuses one or more multivoice radios to synchronize timing for othermultivoice radios in the multivoice system. In this application, amultivoice radio that synchronizes timing for other multivoice radiosand/or provides commands to other radios is referred to as a master. Amultivoice radio that receives timing synchronization and/or commandsfrom a master is referred to as a slave. Several embodiments of thepresent invention are directed toward a multivoice system that has anability to change which radio in the multivoice system performs masterfunction(s) (e.g., supplying timing information and/or sending commandsto other radios in the multivoice system). Several embodiments of thepresent invention are directed toward how a master is initially created.Several embodiments are directed toward how one or more functions of amaster are handed from one MVR to another MVR. Some embodiments aredirected toward how two or more masters are created. Some embodimentsare directed toward how a first master radio can join, or rejoin, as aslave or as a master, a wireless-conferencing system that has a masteralready.

In some embodiments, a multivoice radio is configured to be both amaster radio and as a slave radio. In some embodiments, the multivoiceradio switches, during operation, between being a master radio and aslave radio.

In some embodiments, a multivoice radio in a multivoice system acts aseither a master or a slave after startup. A first radio comprises areceiver configured to receive wireless communication from a secondradio and a third radio using time-division multiplexing. The firstradio comprises a transmitter configured to transmit wirelesscommunication to the second radio and to the third radio usingtime-division multiplexing. The first radio further compriseselectronics configured to search for a wireless transmission from amaster radio so that the multivoice voice radio can act as a slave;determine that the first radio did not receive a qualifying transmissionfrom a master radio; and become a master radio based on not finding amaster radio. In some embodiments a qualifying transmission is atransmission from another radio, received by the first radio, that has apower above a predetermined threshold. In some embodiments, acting asthe master radio includes providing timing information for time-divisionmultiplexing and/or assigning other radios to a transmission slot fortime-division multiplexing.

In some embodiments, a first radio, acting as a slave in a multivoicesystem, transmits a request to a second radio, acting as a master in themultivoice system, for the first radio to become a master of themultivoice system. Some exemplary steps include: the first radio acts asa slave in the multivoice system; the first radio transmits a request tothe second radio asking the second radio for the first radio to bemaster of the multivoice system; and the first radio starts performingmaster function(s) in the multivoice system. In some embodiments, thesecond radio acts as a slave in the multivoice system before,concurrently, and/or after the first radio starts performing masterfunction(s) in the multivoice system.

In some embodiments, a first radio, acting as a master in a multivoicesystem, transmits a request to a second radio, acting as a slave in themultivoice system, for the second radio to become a master of themultivoice system. In some embodiments, this is done when the firstradio receives a power-off command and/or a command to enter alisten-only mode. Some exemplary steps include: the first radio performsmaster functions; the first radio determines to pass off the masterfunctions to a slave radio; the first radio transmits a request to thesecond radio, a slave in the multivoice system, for the slave to performmaster functions; and the first radio receives confirmation from thesecond radio that the second radio will perform master functions.

In some embodiments, a first radio, acting as a slave in a multivoicesystem, becomes a master of the multivoice system when the first radiono longer receives communications from a second radio that was acting asthe master in the multivoice system. Some exemplary steps include: thefirst radio acts as a slave in the multivoice system; the first radiodetermines that transmissions from the second radio are not beingreceived; and the first radio determines to perform one or more masterfunctions for the multivoice system based on not receiving transmissionsfrom the second radio.

In some embodiments, a first radio, acting as a master in a firstmultivoice system, becomes a slave of a second radio, the second radioacting as a master in a second multivoice system. Some exemplary stepsinclude: the first radio performs one or more functions in the firstmultivoice system; the first radio determines that the second radio istransmitting; the first radio determines to join the second multivoicesystem; and the first radio acts as a slave in the second multivoicesystem.

In some embodiments, a first radio, acting as a slave in a firstmultivoice system, switches to become a slave in a second multivoicesystem. Some exemplary steps include: the first radio acts as a slave toa second radio, the second radio acting as the master in the firstmultivoice system; the first radio receives transmissions from a thirdradio, the third radio acting as a master in the second multivoicesystem; a signal strength of transmissions from the third radio arestronger than a signal strength of transmissions from the second radio;and the first radio joins the second multivoice group, as a slave, basedon the signal strength of transmissions from the third radio beingstronger than the signal strength of transmissions from the secondradio. In another example: the first radio acts as a slave to a secondradio, the second radio acting as the master in the first multivoicesystem; the first radio receives transmissions from a third radio, thethird radio acting as a master in the second multivoice system; thefirst radio compares received signal strengths from the second radio andthe third radio; and the first radio determines to join the secondmultivoice group, as a slave, based on comparing received signalstrengths from the second radio and the third radio.

Further areas of applicability of the present disclosure will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating various embodiments, are intended for purposes ofillustration only and are not intended to necessarily limit the scope ofthe disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is described in conjunction with the appendedfigures:

FIGS. 1A and 1B illustrate block diagrams of embodiments a multivoicesystem.

FIGS. 1C and 1D illustrate flowcharts of embodiments of processes for amultivoice radio becoming a master radio or slave radio at startup.

FIG. 1E illustrates a flowchart of an embodiment of a process for aslave radio to request becoming a master after joining a new multivoicesystem or after another radio becomes a master of an existing multivoicesystem.

FIG. 1F illustrates a flowchart of an embodiment of a process for amultivoice radio that is acting as a master to become a slave.

FIG. 2A illustrates a flowchart of an embodiment of a process for amaster radio in a multivoice system to hand off master function(s) to aslave radio at power off.

FIGS. 2B and 2C illustrate flowcharts of embodiments of processes for amaster radio in a multivoice system to hand off master function(s) to aslave radio when entering listen-only mode.

FIG. 3 illustrates a flowchart of an embodiment of a process for a slaveradio in a multivoice system to take over master function(s) after beingrequested to do so.

FIGS. 4A-4D illustrate flowcharts of embodiments of processes for amultivoice radio, acting as a slave in a multivoice system, to act as amaster radio in the multivoice system upon determining the previousmaster radio is no longer transmitting.

FIGS. 5A and 5B illustrate flowcharts of embodiments of processes for afirst master radio to join a multivoice system of a second master radio.

FIG. 6 illustrates a flowchart of an embodiment of a process for a slaveradio to leave a first multivoice system having a first master to join asecond multivoice system having a second master.

In the appended figures, similar components and/or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If only the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

DETAILED DESCRIPTION

The subject matter of embodiments of the present invention is describedhere with specificity to meet statutory requirements, but thisdescription is not necessarily intended to limit the scope of theclaims. The claimed subject matter may be embodied in other ways, mayinclude different elements or steps, and may be used in conjunction withother existing or future technologies. This description should not beinterpreted as implying any particular order or arrangement among orbetween various steps or elements except when the order of individualsteps or arrangement of elements is explicitly described.

With reference to FIGS. 1A and 1B, block diagrams of embodiments amultivoice system are illustrated. In FIG. 1A, a diagram of anembodiment of a wireless-conferencing system forming a multivoice systemis shown. The wireless-conferencing system comprises a master radio 101,a first slave radio 102-1, and a second slave radio 102-2. The masterradio 101, the first slave radio 102-1, and the second slave radio 102-2are MVRs. In this embodiment, the wireless-conferencing system usestime-division multiplexing, such as a time division multiple access(TDMA) protocol for the master radio 101 and the slave radios 102 tocommunicate with each other without using a base station. To implementTDMA, a time period is divided into a plurality of transmission slots.For example, a transmission slot could be about three milliseconds andthere could be eight transmission slots for a twenty-four millisecondtime period. An MVR transmits during none, one, or multiple transmissionslots and receives transmissions (i.e., “listens”) to other MVRs duringone or more transmission slots. In some embodiments, an MVR transmitsduring only one transmission slot and listens during the remainingtransmission slots. The master radio 101 performs one or more masterfunctions. Examples of master functions include providing timingsynchronization data (also referred to as timing data, synchronizationdata, and/or timing synchronization) for a multivoice system, assigningtransmission slots to slave radios 102, assigning the master radio 101,itself, to one or more transmission slots, and sending other commands,such as for a slave to become a master.

In FIG. 1B, a diagram of an embodiment of a multivoice system having twomaster radios is shown. In this embodiment, a second master radio 101-2(an MVR) is within range of the first slave radio 102-1 and the secondslave radio 102-2. The first slave radio 102-1 and the second slaveradio 102-2 have switched from a first multivoice system where the firstmaster 101-1 performs master function(s) to a second multivoice systemwhere the second master radio 101-2 performs master function(s). In someembodiments, the first master 101-1 still receives transmissions formthe first slave 102-1 and/or the second slave 102-2, but the firstmaster 101-1 does not transmit to the first slave 102-1 and/or thesecond slave 102-2. In some embodiments, the first master 101-1 willjoin, as a slave, the second multivoice system. In some embodimentsbelow, different scenarios are described how a multivoice radiodetermines if the multivoice radio is going to be a master radio 101 ora slave radio 102; how a master radio 101 becomes a slave radio 102; howa slave radio 102 becomes a master radio 101; and how a slave radio 102determines whether to stay in a multivoice system with the first masterradio 101-1 or to switch to a multivoice system with the second masterradio 101-2.

With reference to FIGS. 1C and 1D, flowcharts of embodiments ofprocesses for a multivoice radio becoming a master radio, or slaveradio, at startup are shown. In FIG. 1C, after a multivoice radio isturned on, and/or initialized, process 100 begins with the multivoiceradio searching for a master radio, step 104. The multivoice radiosearches for the master radio by waiting to receive transmission fromthe master radio. At step 108, the multivoice radio determines whetheror not a master radio is found. If a master radio is found at step 108,the multivoice radio synchronizes with the master radio, thus acting asa slave to the master radio, step 112. In some embodiments, themultivoice radio synchronizes with the master radio by receiving atransmission-slot assignment from the master radio. In some embodiments,the multivoice radio synchronizes with the master radio and acts as aslave by receiving timing data from the master radio. In someembodiments, the master radio is considered found, in step 108, if themultivoice radio receives a transmission from the master radio that hasa power exceeding a predetermined threshold. In some embodiments, themultivoice radio will take a plurality of power measurements from themaster radio transmission over multiple transmissions and determine ifthe power measurements are increasing or decreasing. In someembodiments, if the power is increasing, then the master is found; ifthe power is decreasing then the master is not found. In someembodiments, if a measurement of the plurality of measurements is abovethe threshold, but the power measurements are decreasing, then themultivoice radio may take further measurements or determine that themaster radio is not found.

If a master radio is not found at step 108, then the multivoice radiocontinues to search for a master until step 116 indicates that a timefor searching is complete. The time for searching may be generated by atimer, a number of search sequences, or other means for determining thata master radio is not in the area. Once the time for searching, step116, is finished and a master radio is not found, process 100 continuesto step 120 where the multivoice radio determines if the multivoiceradio is in listen-only mode. In some embodiments, listen-only mode isdetermined by a microphone of the multivoice radio being connected ordisconnected. If the microphone is disconnected, then the multivoiceradio is in listen-only mode. In some embodiments, whether or not themultivoice radio is in listen-only mode in step 120 is determined by amute button or switch that is triggered. A multivoice that is in listenonly mode at step 120 continues to search for a master, 104. Amultivoice radio that is not in listen-only mode at step 120 continuesto act as master for a multivoice system, step 124. In some embodiments,a multivoice radio has a software and/or hardware flag that prevents themultivoice radio from becoming a master, which, in some embodiments,would be equivalent to the multivoice radio being in listen-only mode atstep 120.

FIG. 1D illustrates a flowchart of an embodiment of process 128 thatshows added functionality using an MVR parameter. MVR parameters can bein hardware (e.g., a jumper or switch) and/or software. One MVRparameter is a master flag parameter. The master flag parameterindicates that the multivoice radio has preference to be a master radioof a multivoice system. When the master flag parameter is set (e.g., bya jumper, or software code set to “yes,” “1,” and/or “on”) then themultivoice radio has preference to become the master radio. After amultivoice radio is turned on, and/or initialized, the multivoice radioenters process 128 at step 104, and searches for master. In step 108,the multivoice radio determines if a master radio is found or not. If amaster radio is found, the multivoice radio synchronizes with the masterradio and acts as a slave, step 112. If a master is not found at step108, then the multivoice radio continues to search for a master radiountil step 116 indicates that the time for searching is complete. Oncethe search is finished, step 116, and a master is still not found, themultivoice radio determines whether or not the master flag parameter isset, step 132. If the master flag parameter is set, then process 128proceeds to step 124 and the multivoice radio acts as a master. In someembodiments, if the master flag parameter is not set, then at step 120the multivoice radio determines if the multivoice radio is inlisten-only mode. If the multivoice radio is in listen-only mode, thenthe multivoice radio continues to search for a master, step 104. If themultivoice radio is not in listen-only mode, the multivoice radio actsas a master, step 124.

With reference to FIG. 1E, a flowchart of an embodiment of a process 136for a slave radio to request becoming a master after joining a newmultivoice system, or after another radio becomes a master of anexisting multivoice system, is shown. Process 136 begins in step 112where the multivoice radio acts as a slave. For example, a multivoiceradio, from process 128, finds a master radio after step 108 and acts asa slave radio in step 112. In step 138, the multivoice radio determinesthe master radio is a new master. The master radio could be a new masterbecause the multivoice radio recently activated, as in process 128. Insome embodiments, step 138 is skipped. For example, a radio with themaster flag parameter is in listen-only mode. When the radio with themaster flag parameter exits listen-only mode, the radio with the masterflag parameter proceeds to step 144 to request to be a master becausethe master flag parameter is set. In some embodiments, a new master isdetermined when a second radio (an MVR) takes over master function(s)from a first radio (also an MVR). Several processes are given below thatprovide examples how a second radio takes over master function(s) from afirst radio. After a determination is made that the master radio is anew master, step 138, the process 136 flows to decision 140 where themultivoice radio determines whether or not the master flag parameter isset for the multivoice radio. If the master flag is not set, themultivoice radio continues to act as a slave, step 112. If the masterflag parameter is set, in step 140, the process 136 flows to step 144where the multivoice radio requests to be master of the multivoicesystem from the new master. The multivoice radio waits for the requestto be master of the multivoice system to be accepted by the masterradio, step 152. If the request is accepted, the multivoice radioassumes the master function(s) and acts as a master, step 124. In someembodiments, the master radio sends a signal to the multivoice radiowhen the request is accepted. If the request is not accepted in step152, the process 136 flows to step 148 where the multivoice radiodetermines whether or not a timeout period for the request has expired.The timeout period can be determined by a lapse of time, a number ofsearch sequences, a number of time periods, or other timing method. Ifthe timeout period has expired, the multivoice radio continues to act asa slave, step 112. If the timeout period has not expired, then process136 returns to step 144 and the multivoice radio either makes a newrequest to the master radio to become master, or the multivoice radiosimply waits for the timeout period to expire. In some embodiments, themultivoice radio waits for a response from the master radio that themaster radio has accepted or rejected the request in step 144, insteadof using a timeout period, step 148. In some embodiments, step 148 isbypassed and the multivoice radio keeps requesting (e.g., each cycle) toact as master until the multivoice radio receives a response from themaster radio (and/or the master stops transmitting during a knowntransmission slot).

With reference to FIG. 1F, a flowchart of an embodiment of a process 156for a master radio to receive a request from a slave radio for the slaveradio to become a master is shown. Process 156 begins in step 124 wherea multivoice radio acts as a master radio for a multivoice system. Instep 160, the multivoice radio receives a request from a second radio(an MVR), the request from the second radio is for the second radio tobecome the master of the multivoice system. The multivoice radiodetermines if the multivoice radio has the master flag parameter set,step 164. If the multivoice radio does not have the master flagparameter set, then the multivoice radio accepts the request from thesecond radio for the second radio to take over master function(s) forthe multivoice system, step 166; and the multivoice radio acts as aslave in the multivoice system, step 112. In some embodiments, themultivoice radio assigns itself a new transmission slot before givingmaster function(s) to the second radio. In some embodiments, themultivoice radio transitions master function(s) to the second radio andthen asks the second radio for a transmission slot.

If in step 164 the multivoice radio determines the master flag parameteris set, then the multivoice radio continues to act as master, returningback to step 124. In some embodiments, if the master flag parameter isset for the multivoice radio, then the multivoice radio transmits adenial to the second radio, step 168, in response to the request fromthe second radio.

In a wireless conference system that has no base station, one of thetransceivers acts as a master as disclosed in the '115 application. Inthe '115 application, one of the radios is programmed to be a masterradio and the master radio lacks the capability to switch between beinga master and a slave. In some applications, having the masterfunction(s) able to switch between multiple radios can be important. Forexample, in a multivoice system of the '115 application, if the masterradio were to be turned off, the multivoice system would stopfunctioning and slave radios in the multivoice system would lose anability to communicate with each other. However, having another radiotake over master function(s) would keep the multivoice system working.For example, if a SWAT team entered a building, and the master radio,outside the building, turns off or gets out of range from slave radios,under the multivoice system in the '115 patent, SWAT team members insidethe building having slave radios would not be able to communicate viathe slave radios. Under some embodiments in this disclosure, if themaster radio is turned off, another radio takes over as the master radioto keep the multivoice system working.

FIG. 2A illustrates a flowchart of an embodiment of a process 200 thatshows a first radio handing off master function(s) in a multivoicesystem to a second radio when the first radio is powered off. The firstradio and the second radio are MVRs. Process 200 begins with the firstradio acting as a master, step 124. The process flows to step 208 wherethe first radio receives a power-off indication. In some embodiments, akeypad is used to turn the first radio off. In some embodiments, aswitch is used to turn the first radio off. In some embodiments,processes in the keypad keep power on long enough to hand masterfunction(s) to a slave radio in the multivoice system. In someembodiments, other techniques are used to hold the power on until masterfunction(s) are handed off. In some embodiments, the master radio mayjust stop working and a slave will take over as a master based on themaster radio no longer transmitting. When the power-off indication isreceived in step 208, process 200 flows to step 236 where actual poweroff of the radio is delayed. After step 236, in step 240 it isdetermined whether or not there are any slaves assigned to atransmission slot. If there are no slaves in a transmission slot in step240, power is turned off for the first radio, step 256.

However, if there are slaves in a transmission slot in step 240 (or ifthere is a radio that can become a master), process 200 flows to step244 where the first radio requests a slave to take over the masterfunction(s) for the multivoice system. If a slave (i.e., the secondradio) accepts the request to take over the master function(s), step252, then the first radio powers off, step 256. In some embodiments,before powering off, the first radio transmits confirmation to thesecond radio and/or all radios in the multivoice system that the secondradio is take over the master function(s). If the request is notaccepted in step 252, the first radio waits for a timeout period, step248. If the timeout period in step 248 expires, the then first radiopowers off, step 256. But if the timeout period in step 248 has notexpired, then process 200 returns to step 240 and the first radiodetermines whether there is a slave assigned to a transmission slot (orif there is a radio that can perform master function(s)). In someembodiments, when there are two or more slaves, the first radio askseach slave sequentially, based on transmission-slot assignment, to takeover the master function. In some embodiments, the first radio transmitsa request to all slave radios at once and accepts a first slave thatresponds. In some embodiments, an additional step is added to process200 where after a slave accepts the request to take the masterfunction(s), the first radio acknowledges to the slave that the firstradio received the slave's acceptance.

With reference to FIGS. 2B and 2C, flowcharts of embodiments ofprocesses for a master radio in a multivoice system to hand off masterfunction(s) to a slave radio when entering listen-only mode are shown.In FIG. 2B, process 201 starts in step 124 where a multivoice radio actsas a master radio for a multivoice system. Process 201 flows from step124 to step 212 where the multivoice radio receives a listen-only modeindication. The listen-only mode indication could be a user toggling aswitch or pushing a button. In some embodiments, the listen-only modeindication is activated by a microphone being unplugged or disabled. Inthe listen-only mode, a radio may receive transmission of other radiosbut does not transmit audio communication during a transmission slot.When the multivoice radio receives the listen-only mode indication, themultivoice radio determines whether or not the master flag parameter isset, step 216. If the master flag parameter is set then process 201returns to step 124 and the multivoice radio continues to act as master.In some embodiments, a master radio that is in listen-only mode canstill serve as a master and transmit data, but the master radio does nottransmit audio information. In some embodiments, a master radio that isin listen-only mode can still serve as a master and transmit data, butthe master radio is not assigned to a transmission slot to transmitaudio communication; instead, the master radio is assigned atransmission slot to transmit data.

If in step 216 the master flag parameter is not set, then process 201flows to step 220 where a determination is made whether or not a slaveradio occupies a transmission slot. If there are no slave radios thatoccupy a transmission slot, then the multivoice radio searches for amaster, step 104. But if there is a slave in a transmission slot in step220, then the multivoice radio requests the slave, a second radio, totake over the master function(s), step 224. In some embodiments, themultivoice radio asks all slaves at once that have transmission slots totake the master function(s), but confirms with only one slave to takethe master function(s). If, in step 228, the request for the secondradio to take over the master function(s) is accepted, then themultivoice radio searches for a master, step 104 (and will presumablyfind the second radio acting as a master radio); or, in someembodiments, the multivoice radio acts as a slave, step 112, to thesecond radio.

If the request in step 228 is not accepted, then process 201 flows tostep 220 where the multivoice radio checks whether there are any slaveradios in a transmission slot, and if so, asks one of the slaves to takethe master function(s). In some embodiments, if the request, in step224, is not accepted after a certain timeout period, the multivoiceradio searches for a master, step 104.

Process 202 in FIG. 2C is similar to process 201 in FIG. 2B, exceptafter step 228, the second radio does not accept the request for thesecond radio to take the master function(s) then the process 202 flowsto step 230 where the multivoice radio determines whether or not thereare other slaves present (i.e., besides the second radio). If there areno other slaves present, then the multivoice radio retains the masterfunction(s) and acts as a master 124. But if there are other slavespresent (i.e., a third radio, wherein the third radio is assigned to atransmission slot), then process returns to step 224 and the multivoiceradio asks the third radio for the third radio to take the masterfunction(s). A loop of steps 224, 228, and 230 continues until themultivoice radio has asked all radios assigned to a transmission slot totake the master function(s); and if there are no other slaves presentthat have not been asked to take the master function(s), the process 202returns to step 124, where the multivoice radio continues to act asmaster. In some embodiments, the multivoice radio searches for a master,step 104, instead of returning to step 124 as described in the previoussentence if the request for another slave to be master is not accepted.

FIG. 3 illustrates a flowchart of an embodiment of a process 300 for aslave radio in a multivoice system to take over master function(s) afterbeing requested to do so. Process 300 begins in step 112 where amultivoice radio acts as a slave in the multivoice system. A transceiverof the multivoice radio is used to determine that a second radio, actingas the master radio, is transmitting a request for the multivoice radioto take over the master function(s), step 308. In some embodiments, aslave radio may be asked to be the master if the slave radio is next inline to become the master based on some algorithm (e.g., round robin,transmission-slot sequence, or known master flag parameters) and/orbased on no other slave being available to become the master. If in step308 the multivoice radio determines that the second radio is asking forthe multivoice radio to be the master, then the multivoice radio acceptsthe request for the multivoice radio to become master, step 312. In step312, a signal may be sent from the multivoice radio to the second radioto indicate acceptance. In some embodiments, the second radio stopstransmitting during an assigned transmission slot to accept the request,step 312, for the multivoice radio to be master.

After step 312, two tests exist, steps 316 and 318, before themultivoice radio takes over master function(s) in step 320. In step 316,the multivoice radio receives confirmation from the second radio thatthe multivoice radio is to become master, and the multivoice radio takesover master function(s), step 320. In step 318, the multivoice radiodetermines that the second radio is no longer transmitting. In someembodiments, the master radio is assigned to transmit on a firsttransmission slot. If no radio transmits on the first transmission slot,then the multivoice radio determines that the second radio is no longertransmitting as master of the multivoice system. After the multivoiceradio determines the master is no longer transmitting, step 318, thenthe multivoice radio takes over master function(s), step 320. In someembodiments, taking over master function(s) includes transmitting duringa transmission slot that the master is normally assigned to. After themultivoice radio takes over master function(s) in step 320, themultivoice radio the acts as master, step 124. In some embodiments,taking over master function(s) and/or acting as master includesbroadcasting to radios in the multivoice system that the multivoiceradio is now acting as master. In some embodiments, taking over masterfunction(s) and/or acting as master includes receiving anacknowledgement from a previous master for the multivoice radio to takeover master function(s). In some embodiments, either test found in step316 or in step 318, when satisfied, is sufficient for the multivoiceradio to take over master function(s), step 320. In some embodiments,both tests found in step 316 and in step 318 must be satisfied beforethe multivoice radio takes over master function(s) in step 320. In someembodiments, steps 316 and/or 318 are bypassed and once the multivoiceradio accepts the request to be master, step 312, process flows to step320 where the multivoice radio takes over master function(s).

FIGS. 4A and 4B illustrate flowcharts of embodiments of processes for amultivoice radio, acting as a slave in a multivoice system, to act as amaster radio in the multivoice system upon determining a previous masterradio is no longer transmitting. For example, the previous master couldhave been turned off, or the previous master and the multivoice radiocould be separated so that the previous master and the multivoice radioare no longer in radio contact with each other. In some embodiments,slave radios still communicate with each other after the previous masteris no longer transmitting by the slave radios transmitting during theirassigned transmission slots. A first slave can use informationtransmitted from one or more other slaves to determine whether or notthe first slave should become a master radio. Signal strength from theprevious master before losing communication with the previous master mayalso be used.

In FIG. 4A, process 400 begins with a multivoice radio acting as aslave, step 112, to a second radio (an MVR) in a multivoice system. Thesecond radio is the previous master. In step 408, the multivoice radiodetermines that the multivoice radio is no longer receiving transmissionfrom the second radio. In some embodiments step 408 is performed by themultivoice radio receiving transmission from the second radio and thetransmission from the second radio is below a power threshold level. Insome embodiments, a master radio transmits during a specifiedtransmission slot. When the multivoice radio no longer receivestransmission during the specified transmission slot (e.g., atransmission that is below the power threshold level), the multivoiceradio determines the multivoice radio is no longer receivingtransmission from the second radio, where the second radio is acting asthe master radio for the multivoice system. When the determination ismade in step 408, process 400 flows to step 412 where the multivoiceradio determines whether or not the multivoice radio is assigned atransmission slot in the multivoice system for transmitting audiocommunication (e.g., not in listen-only mode). In some embodiments, step412 is used to determine whether or not there is another radio that iscapable of becoming a master. In some embodiments a slave radio has aparameter that prevents the slave radio from becoming a master radio. Ifthe multivoice radio is assigned a transmission slot (or in someembodiments if the multivoice radio can become a master radio, whetheror not assigned a transmission slot), process 400 flows to process 416,discussed in FIG. 4B, to determine whether or not the multivoice radiois to become the master for the multivoice system.

If the multivoice radio determines that the multivoice radio occupies atransmission slot in step 412 (e.g., having been assigned a transmissionslot by the master of the multivoice system), then process 400 flows tostep 420 where the multivoice radio waits for a new master. In step 424,the multivoice radio determines whether or not a new master istransmitting. In some embodiments, the master radio of the multivoicesystem transmits during a known transmission slot (e.g., transmissionslot 1). Another radio in the multivoice system, such as a slaveassigned to transmission slot 2, could take over master function(s) andstart transmitting during transmission slot 1; then the multivoice radiowould know there is a new master for the multivoice system. When themultivoice radio determines a new master is transmitting, the multivoiceradio returns to acting as a slave, step 112 (and in some embodimentswould proceed to process 136 in FIG. 1E and determine there is a newmaster in step 138).

If a new master is not found in step 424, process 400 flows to step 428where the multivoice radio determines whether a timeout period hasexpired for waiting for the new master. If the timeout period has notexpired, then the multivoice radio waits for a new master, step 420. Insome embodiments, if the timeout period has not expired, then themultivoice radio returns to acting as a slave, step 112. If the timeoutperiod has expired and a new master has not taken control of themultivoice system, then the multivoice radio searches for a new master,step 104.

In FIG. 4B, process 416 starts at step 432 where the multivoice radiodetermines whether or not the multivoice radio is next in line to becomethe master of the multivoice system. In some embodiments, next in lineis determined by a priority algorithm built into the multivoice systemor programmed in as a parameter for the multivoice radio. In someembodiments, the next in line is based on a transmission slot assignmentof a slave radio. For example, for a first slave radio assigned totransmission slot 2, a second slave radio assigned to transmission slot3, and a third slave radio assigned to transmission slot 4, the next inline would be the first slave radio first, the second slave radiosecond, and the third slave radio third. If the multivoice radio is nextto be master in step 432, the multivoice voice radio takes over masterfunction(s), step 320 and acts as master, step 124.

If the multivoice radio is not next to be master in step 432, themultivoice radio waits for a new master, step 436. In step 440, themultivoice radio determines if there is a new master. If there is a newmaster, then the multivoice radio acts as a slave, step 112 (and in someembodiments, also proceeds to process 136 in FIG. 1E to determine a newmaster in step 138). If in step 440 a new master is not found, then themultivoice radio determines if a timeout period has expired, step 444.If the timeout period has expired, the multivoice radio searches for amaster, step 104; if the timeout period has not expired, the multivoiceradio returns to determining if the multivoice radio is next to bemaster, step 432.

In some embodiments, it is noted that there is a possibility of threedifferent periods of “time.” First, a time period that is subdividedinto transmission slots for the time-division multiplexing; second, await period in step 436; and third, a timeout period in step 444. It isnoted that a duration of the time period that is subdivided intotransmission slots can be referred to as a cycle. And durations of thewait period and/or the timeout period can be based on an internal clockand/or a number of cycles based on assigned transmission slot. Thefollowing example is for a scenario where a master transmits during slot0, a first slave transmits during slot 1, a second slave transmitsduring slot 2, and a third slave transmits during slot 4 (slot 3 beingpreviously abandoned or not assigned). If the master radio stoppedtransmitting during slot 0, the first slave, the second slave, and thethird slave would each follow steps 112 (act as slave), 408 (determineradio is no longer receiving transmission from master), and 412 (doesthis radio occupy a transmission slot) bringing them to process/step 416(determine whether or not to become a master) in process 400. In someembodiments, determining that the master is no longer transmittingincludes monitoring no transmission (or transmission below a threshold)during slot 0 for a given number of cycles (e.g., 1, 2, 3, 4, 5, 7, or10 cycles). In step 432 (is this radio next to be master?) of process416, the first slave would become master based on the first slave beingassigned a transmission slot having a lowest number compared to othertransmission slot numbers. The second slave and the third slave wouldproceed to step 436 to wait for another slave to be master. In someembodiments, the wait period during step 436 is a number of cycles(e.g., 1, 2, 3, 4, or 5). In this example, the wait period is one cycle.If after one cycle the second first slave does not transmit during slot0 (for whatever reason), then the second slave, in step 432, would benext in line based on transmission slot number and a number of cycleslapsed since determining the master is no longer transmitting in step408; and the third slave would proceed to step 436 to wait anothercycle. The timeout period in step 444 can be based on a number of cycles(e.g., 5, 10, 17, 20, 25, or 50) or a clock time (e.g., 0.10, 0.25, 0.5,0.75, 1, or 2 seconds). Generally the time timeout period is longer thanthe wait period, but does not need to be. Following the example above,the second slave has a timeout period of three cycles because the secondslave is in the second slot and the third slave has a timeout period twocycles longer than the second slave because the third slave is in thefourth slot.

FIGS. 4C and 4D illustrate additional flowcharts of embodiments ofprocesses for a multivoice radio, acting as a slave in a multivoicesystem, to act as a master radio in the multivoice system upondetermining the previous master radio is no longer transmitting. It willbe appreciated that steps in FIGS. 4A and 4B can be removed and/or newsteps added based on desired functionality. FIGS. 4C and 4D are providedto give additional examples for a multivoice radio acting as a slave tobecome master of the multivoice system when a previous master stopstransmitting (e.g., is separated from the multivoice radio).

The first three steps of process 448 in FIG. 4C are similar to the firstthree steps of process 400 in FIG. 4A. A multivoice radio acts as aslave in a multivoice system, step 112; the multivoice radio determinesthe multivoice radio is no longer receiving transmissions from a masterradio of the multivoice system, step 408; and the multivoice radiodetermines whether or not the multivoice radio occupies a transmissionslot of the multivoice system, step 412. If the multivoice radio doesnot occupy a transmission slot, then the multivoice radio searches for amaster, step 104 instead of waiting as in step 420 of process 400.

If the multivoice radio is assigned a transmission slot in step 412,then the multivoice radio determines whether or not there are otherslaves in the multivoice system, step 452. If there are no other slaves(e.g., the multivoice radio is the only slave assigned a transmissionslot in the multivoice system), then the multivoice radio searches for amaster, step 104. But if the multivoice radio determines there are otherslaves in step 452, then process 448 flows to process/step 416 todetermine whether or not the multivoice radio takes over masterfunction(s).

Referring next to FIG. 4D, the first two steps of process 456 in FIG. 4Dare similar to the first two steps of process 400 in FIG. 4A. Amultivoice radio acts as a slave in a multivoice system, step 112; andthe multivoice radio determines the multivoice radio is no longerreceiving transmissions from a master radio of the multivoice system,step 408. After determining that the multivoice radio is no longerreceiving transmissions from a master radio of the multivoice system instep 408, the multivoice radio determines whether or not the multivoiceradio has a master flag parameter identified, step 460. If themultivoice radio does not have the master flag parameter, then themultivoice radio searches for a master, step 104. If the multivoiceradio has the master flag parameter, then from step 460 the multivoiceradio takes over master function(s), step 320, and acts as master, step124.

Further variations are possible. For example, in some embodiments, if acertain number, a majority, or all slave radios have lost thecommunication with a master radio, then the multivoice radio takes overmaster function(s), step 320. In some embodiments, all slave radios thatoccupy transmission slots must lose communication with the master radiobefore another radio takes over the master function(s) in step 320.

FIGS. 5A and 5B illustrate flowcharts of embodiments of processes for afirst master radio to join a multivoice system of a second master radio.For example, there are twenty members of a SWAT (Special Weapons AndTactics) team, each member having an MVR (some MVRs in listen-onlymode). A team of five SWAT team members enters a building while fifteenSWAT team members remain outside. The five SWAT team members lose radiocontact with a first master radio, the first master radio being with aSWAT team member who remains outside the building. One MVR of the fiveSWAT team members takes over master function(s) as discussed above andbecomes a second master. When the five SWAT team members rejoin thefifteen SWAT team members there are two master radios and two multivoicesystems, a first master for the multivoice system of the fifteen SWATteam members and a second master for the multivoice system of the fiveSWAT team members. Several embodiments below disclose how radios fromtwo multivoice systems can become part of one multivoice system.

Referring next to FIG. 5A, process 500 begins with a multivoice radioacting as a first master, step 124, for a first multivoice system. Themultivoice radio searches to receive transmission from other masterradios. If another master radio is found, then the multivoice radiodetermines that a second master, of a second multivoice system, istransmitting, step 508, and process 500 flows to step 512. In step 512,the multivoice radio determines whether or not the second master'ssignal is strong. In some embodiments, determining whether or not thesecond master's signal is strong is done using a received signalstrength indicator from an RF section of the multivoice radio. If thereceived signal is weak, that may indicate that the second master is toofar away or at and edge of a range of the multivoice radio. If thesignal is weak, a counter or timer may be used to ensure the secondmaster stays in the area before the multivoice radio joins the secondmultivoice system. If the signal is weak, or not there long enough, thenthe multivoice radio continues to act as master, step 124, for the firstmultivoice system. In some embodiments, step 512 is skipped.

If the second master's signal is strong enough in step 512 (e.g., abovea specified threshold), the multivoice radio determines whether or notone, some, or all slaves in the first multivoice system have left tojoin the second multivoice system. In some embodiments, determiningwhether or not slave radios have left is performed by having a slaveradio send information to other radios in a multivoice system that theslave is moving to another multivoice system. If slave radios in thefirst multivoice system have not left the first multivoice system instep 516, then the multivoice radio acts as master, step 124, for thefirst multivoice system.

If in step 516 the multivoice radio determines that one, some, or allradios have left the first multivoice system, the multivoice radiodetermines to join the second multivoice system and sets timing, step520 to the second multivoice system and acts as a slave, step 112, inthe second multivoice system. In some embodiments, if the multivoiceradio determines that one, some, or all radios have left the firstmultivoice system in step 516, then the multivoice radio starts tosearch for a master, step 104 (and will likely find the second master instep 108 of process 100). In some embodiments, setting timing to thesecond master in step 520 allows the multivoice radio to more quicklyjoin the second multivoice system than simply searching for a master asin step 104.

In some embodiments, whether or not a slave is in a transmission slot ofthe second multivoice system, step 518, is also used to determinewhether or not the multivoice radio joins the second multivoice system.Step 518 can be used in place of, or in conjunction with, step 516 toform a second test. In some embodiments, both the test in step 516 andthe test in step 518 must be satisfied before the multivoice radio joinsthe second multivoice system. In some embodiments, if either the test instep 516 or the test in 518 is met, then the multivoice radio joins thesecond multivoice system.

Referring next to process 524 in FIG. 5B, the first three steps inprocess 524 are similar to the first three steps in process 500 of FIG.5A: a multivoice radio acts as a first master to a first multivoicesystem, step 124; the multivoice radio determines that a second masterof a second multivoice system is transmitting, step 508; and themultivoice radio determines if the second master's signal is strong,step 512. If the multivoice radio determines that the second master'ssignal is strong in step 512, then the multivoice system determineswhether or not the multivoice system has a master flag parameter, step528. If the multivoice radio does not have the master flag parameterthen the multivoice radio searches for a master, step 104. If themultivoice radio has the master flag parameter, then the multivoiceradio continues to act as a master, step 124, or the multivoice radiodetermines whether or not there is a slave in a transmission slot of thefirst multivoice system, step 532. If there is slave in the firstmultivoice system, step 532, then the multivoice radio remains master ofthe first multivoice system, step 124. If there is not a slave in thefirst multivoice system, at step 532, then the multivoice radio searchesfor a master, step 104. In some embodiments, instead of searching for amaster, step 104, in response to there not being a slave in the firstmultivoice system, the multivoice radio sets timing to the secondmultivoice system, step 520, and acts as a slave, step 112.

FIG. 6 illustrates a flowchart of an embodiment of a process 600 for aslave radio to leave a first multivoice system having a first master tojoin a second multivoice system having a second master. A multivoiceradio enters process 600 as a slave radio, step 112-1, to a first masterin a first multivoice system. In some embodiments, as part of step112-1, the multivoice radio searches for other masters. In step 608, themultivoice radio receives transmission from a second master in a secondmultivoice system. In step 612, if transmission from the second masteris stronger than transmission from the first master, the multivoiceradio sets timing of the multivoice radio to the second master, step620, and acts as a slave, step 112-2, to the second master. If in step612 the signal of the second master is weaker than the signal of thefirst master, then the multivoice radio continues to act as a slave tothe first master, step 112-1. For example, in some embodiments, thefirst master and the second master both transmit during one transmissionslot. When the first master is closer to the multivoice radio than thesecond master, the multivoice radio receives transmissions from thefirst master because a received signal from the first master is stronger(assuming the first master and the second master have equal poweroutput) than a received signal from the second master. When the firstmaster and the second master are equidistant from multivoice radio, thefirst master and the second master effectively jam each other. But asthe second master gets closer to the multivoice radio, the multivoiceradio receives transmission from the second master because a receivedtransmission from the second master is stronger than a receivedtransmission from the first master. The multivoice radio recognizes thatthe multivoice radio is closer the second master and sets timing to thesecond master, step 620. In some situations, closeness is determined byradio transmission and not necessarily by physical distance. Forexample, a second master 100 feet away from the multivoice radio may be“closer” to the multivoice radio than a first master that is ten feetaway but on an opposite side of a thick concrete wall having heavy rebar(transmissions from the first master to the multivoice radio beingstrongly attenuated by the concrete wall).

In some embodiments, after receiving transmission from the second masterin step 608, the multivoice radio compares signal strength of the firstmaster to signal strength of the second master, step 612. In someembodiments, comparing signal strength is done using the received signalstrength indicator from an RF section of the multivoice radio. If thesignal strength of either the first master or the second master is weak,that may indicate that the first master and/or the second master are atan edge of a range of the multivoice radio. If a signal from the secondmaster radio is weak, a counter, or timer, may be used to make sure thesecond master stays in the area before joining with the secondmultivoice group. In some embodiments, step 612 is skipped and themultivoice radio joins the second multivoice system, step 620. In someembodiments, if the multivoice radio determines transmissions from thesecond master is stronger than transmissions from the first master, instep 612, then the multivoice radio starts to search for a master, step104 (and will likely find the second master in step 108 of process 100),instead of setting timing to the second master, step 620. In someembodiments, setting timing to the second master in step 620 allows themultivoice radio to more quickly join the second multivoice system thansimply searching for a master, as in step 104.

In some embodiments, whether or not there are slaves in the secondmultivoice system, step 616, is also used to determine whether or notthe multivoice radio joins the second multivoice system. Step 616 can beused in place of, or in conjunction with, step 612 to form a secondtest. In some embodiments, both the test in step 612 and the test instep 616 must be satisfied before the multivoice radio joins the secondmultivoice system. In some embodiments, if either the test in step 612or the test in 616 is met, then the multivoice radio joins the secondmultivoice system.

In some embodiments, the multivoice radio joins the second multivoicesystem after receiving a signal from the first master radio that thefirst master radio is joining the second multivoice system. In someembodiments, the multivoice radio simply joins whichever master has astronger signal, because the first master and the second master may betransmitting during a same transmission slot.

Though specific examples were given in the above description, there canbe several variations to the embodiments described. For example, when amaster radio asks a slave radio to take over master function(s) therecan be a three-way handshake: (1) the master radio transmits a requestto the slave radio asking if the slave will the master; (2) the slaveradio transmits a response to the master radio that the slave radio willbe the master; and (3) the master radio either (a) transmits a responseto the slave radio confirming that the master radio received thetransmission from the slave radio for the slave radio to be the master,or (b) the master radio stops transmitting on a master transmissionslot. In some embodiments, the transmission in (3)(a) above for themaster radio transmitting a response to the slave radio is transmittedto all slave radios.

In some embodiments, a four-way handshake is made to transfer masterfunction(s) from a master radio to a slave radio: (1) the slave radiotransmits a request to the master radio for the slave radio to take themaster function(s) (e.g., step 144 of process 136 in FIG. 1E), and (1-3)are the same as the three-way handshake in the previous paragraph.

In some embodiments, a slave has a switch so that the slave won'ttransfer from a first master to a second master. In some embodiments,radio transmission includes direct sequence spread spectrumcommunication, frequency hopping spread spectrum communication, and/orsingle channel communication. In some embodiments, other multiple accessprotocols, such as code division multiple access (CDMA),Frequency-division multiple access (FDMA), and/or space divisionmultiple access (SDMA) are used in conjunction with, or in lieu of,TDMA.

Specific details are given in the above description to provide athorough understanding of the embodiments. However, it is understoodthat the embodiments may be practiced without these specific details.For example, circuits may be shown in block diagrams in order not toobscure the embodiments in unnecessary detail. In other instances,well-known circuits, processes, algorithms, structures, and techniquesmay be shown without unnecessary detail in order to avoid obscuring theembodiments.

Implementation of the techniques, blocks, steps and means describedabove may be done in various ways. For example, these techniques,blocks, steps and means may be implemented in hardware, software, or acombination thereof. For a hardware implementation, the processing unitsmay be implemented within one or more application specific integratedcircuits (ASICs), digital signal compounders (DSPs), digital signalprocessing devices (DSPDs), programmable logic devices (PLDs), fieldprogrammable gate arrays (FPGAs), processors, controllers,micro-controllers, microprocessors, other electronic units designed toperform the functions described above, and/or a combination thereof.

Also, it is noted that the embodiments may be described as a processwhich is depicted as a flowchart, a flow diagram, a swim diagram, a dataflow diagram, a structure diagram, or a block diagram. Although adepiction may describe the operations as a sequential process, many ofthe operations can be performed in parallel or concurrently. Inaddition, the order of the operations may be re-arranged, steps added,and/or steps removed depending on particular applications. One ofordinary skill in the art would recognize many variations,modifications, and alternatives. A process is terminated when itsoperations are completed, but could have additional steps not includedin the figure. A process may correspond to a method, a function, aprocedure, a subroutine, a subprogram, etc. When a process correspondsto a function, its termination corresponds to a return of the functionto the calling function or the main function.

Furthermore, embodiments may be implemented by hardware, software,scripting languages, firmware, middleware, microcode, hardwaredescription languages, and/or any combination thereof. When implementedin software, firmware, middleware, scripting language, and/or microcode,the program code or code segments to perform the necessary tasks may bestored in a machine readable medium such as a storage medium. A codesegment or machine-executable instruction may represent a procedure, afunction, a subprogram, a program, a routine, a subroutine, a module, asoftware package, a script, a class, or any combination of instructions,data structures, and/or program statements. A code segment may becoupled to another code segment or a hardware circuit by passing and/orreceiving information, data, arguments, parameters, and/or memorycontents. Information, arguments, parameters, data, etc. may be passed,forwarded, or transmitted via any suitable means including memorysharing, message passing, token passing, network transmission, etc.

For a firmware and/or software implementation, the methodologies may beimplemented with modules (e.g., procedures, functions, and so on) thatperform the functions described herein. Any machine-readable mediumtangibly embodying instructions may be used in implementing themethodologies described herein. For example, software codes may bestored in a memory. Memory may be implemented within the processor orexternal to the processor. As used herein the term “memory” refers toany type of long term, short term, volatile, nonvolatile, or otherstorage medium and is not to be limited to any particular type of memoryor number of memories, or type of media upon which memory is stored.

Moreover, as disclosed herein, the term “storage medium” may representone or more memories for storing data, including read only memory (ROM),random access memory (RAM), magnetic RAM, core memory, magnetic diskstorage mediums, optical storage mediums, flash memory devices and/orother machine readable mediums for storing information. The term“machine-readable medium” includes, but is not limited to portable orfixed storage devices, optical storage devices, and/or various otherstorage mediums capable of storing that contain or carry instruction(s)and/or data.

While the principles of the disclosure have been described above inconnection with specific apparatuses and methods, it is to be clearlyunderstood that this description is made only by way of example and notas limitation on the scope of the disclosure.

What is claimed is:
 1. A radio configured to switch from being a firstmaster radio to becoming a slave radio to a second master radio, theradio comprising: a receiver configured to: receive a first wirelesscommunication, wherein: the radio is a first radio; the first radio is amobile, handheld radio; the first radio receives the first wirelesscommunication from a second radio; and the second radio is a mobile,handheld radio; and the first radio receives the first wirelesscommunication using a multiple access protocol; receive a secondwireless communication, wherein: the first radio receives the secondwireless communication from a third radio; the third radio is a mobile,handheld radio; and the first radio receives the second wirelesscommunication using the multiple access protocol; a transmitterconfigured to: transmit wireless communication to the second radio usingthe multiple access protocol; and transmit wireless communication to thethird radio using the multiple access protocol, wherein the first radiois configured to: function as a first master radio for receiving thefirst wireless communication and transmitting wireless communication tothe second radio; function as a slave radio, before powering off andafter receiving the first wireless communication, to the third radio forreceiving the second wireless communication and transmitting to thethird radio, such that the third radio is a second master radio;determine a strength of a signal received from the second master radiowhile the first radio functions as the first master radio; determinethat the strength of the signal received from the second master radio isgreater than a predetermined threshold; and switch from functioning asthe first master radio to functioning as the slave radio to the secondmaster radio based on determining that the strength of the signalreceived from the second master radio is greater than the predeterminedthreshold.
 2. The radio as recited in claim 1, wherein the multipleaccess protocol is time division multiple access.
 3. The radio asrecited in claim 1, wherein the first radio is configured to verify thatthe third radio is not assigned to a transmission slot of a wirelessconferencing group between receiving the first wireless communicationand receiving the second wireless communication.
 4. The radio as recitedin claim 1, wherein the first radio is configured to enter asearch-for-master routine between receiving the first wirelesscommunication and receiving the second wireless communication.
 5. Theradio as recited in claim 1, wherein the first radio is configured toverify, after the first wireless communication and before the secondwireless communication, that the second radio is no longer a slave radioto the first radio.
 6. The radio as recited in claim 5, wherein thefirst radio is configured to verify, after the first wirelesscommunication and before the second wireless communication, that thesecond radio became a slave radio to the second master radio.
 7. Theradio as recited in claim 1, wherein the first radio is configured toverify, after the first wireless communication and before the secondwireless communication, that the first radio has no slave radios.
 8. Theradio as recited in claim 1, wherein: the first radio is configured totransmit the first wireless communication to the second radio and to thethird radio concurrently; and the third radio is a slave radio to thefirst radio after the first wireless communication and before the secondwireless communication, without turning off between the first wirelesscommunication and the second wireless communication.
 9. A method for afirst master radio to become a slave radio to a second master radio, themethod comprising: transmitting, using a first radio, a first wirelesscommunication, wherein: the first wireless communication is transmittedfrom the first radio to a second radio; the first wireless communicationuses a multiple access protocol; the first radio is a mobile, handheldradio; the first radio is a first master radio; the second radio is amobile, handheld radio; and the second radio is a slave to the firstradio; receiving, using the first radio, a second wirelesscommunication, wherein: the second wireless communication uses themultiple access protocol; the second wireless communication istransmitted from a third radio; the third radio is a mobile, handheldradio; and the third radio is a second master radio; and switching fromtransmitting as the first master radio to receiving as a slave radio tothe second master radio, wherein: the first radio is configured to:determine a strength of a signal received from the second master radiowhile the first radio is the first master radio; and determine that thestrength of the signal received from the second master radio is greaterthan a predetermined threshold; switching from transmitting as the firstmaster radio to receiving as the slave radio to the second master radiois based on determining that the strength of the signal received fromthe second master radio is greater than the predetermined threshold; andswitching occurs between the first wireless communication and the secondwireless communication without powering off.
 10. The method as recitedin claim 9, wherein: the first radio and the second radio communicatedirectly with each other without a base station; and the first radio andthe third radio communicate directly with each other without the basestation.
 11. The method as recited in claim 9, wherein transmitting asthe first master radio includes providing data, for timingsynchronization, in the first wireless communication the second radio.12. The method as recited in claim 9, wherein receiving as the slaveradio to the second master includes receiving, using the first radio,data from the third radio for a slot assignment in a time divisionalmultiple access protocol.
 13. The method as recited in claim 9 furthercomprising determining that the third radio has a parameter indicatingthat the third radio has a preference to be a master radio, wherein thefirst radio switches from being the first master radio to becoming aslave radio to the second master radio based on determining that thethird radio has the parameter.
 14. The method as recited in claim 9further comprising verifying, after the first wireless communication andbefore the second wireless communication, that the second radio is nolonger a slave radio to the first radio.
 15. A radio system for a firstmaster radio to become a slave to a second master radio, the radiosystem comprising: a first radio, wherein: the first radio is a mobile,handheld radio; the first radio is configured to transmit a firstwireless communication, as a first master radio, to a second radio usinga multiple access protocol; the first radio is configured to receive asecond wireless communication from a third radio using the multipleaccess protocol; and the first radio is configured to: switch fromtransmitting as the first master radio to receiving as a slave radio toa second master radio; determine a strength of a signal received fromthe second master radio while the first radio functions as the firstmaster radio; and determine that the strength of the signal receivedfrom the second master radio is greater than a predetermined threshold,wherein: switching occurs between the first wireless communication andthe second wireless communication, without the first radio powering off;and switching is based on determining that the strength of the signalreceived from the second master radio is greater than the predeterminedthreshold; the second radio, wherein: the second radio is a mobile,handheld radio; and the second radio is a slave to the first masterradio during the first wireless communication; the second radio isconfigured to receive the first wireless communication using themultiple access protocol; and a third radio, wherein: the third radio isa mobile, handheld radio; the third radio is configured to transmit, asthe second master radio, the second wireless communication using themultiple access protocol.
 16. The radio system as recited in claim 15,wherein: the multiple access protocol is time division multiple access;the first wireless communication uses a first timing synchronization;and the second wireless communication uses a second timingsynchronization, wherein the first timing synchronization is differentthan the second timing synchronization.
 17. The radio system as recitedin claim 15, wherein the third radio, without turning off, was a slaveradio to the first radio after the first wireless communication andbefore the second wireless communication.
 18. The radio system asrecited in claim 15, wherein the first radio is configured to verify,after the first wireless communication and before the second wirelesscommunication, that the first radio has no slave radios.
 19. The radiosystem as recited in claim 15, wherein: the first radio and the secondradio communicate directly with each other without a base station; andthe first radio and the third radio communicate directly with each otherwithout the base station.